My video file won't open
You will have to delete the strips in the Video Sequence editor windows.
Rendering to windows will work after you removed them.

What happened?

Basically the creator of the blend file have already rendered out the sequence of frames on his computer. He has also imported them as sequence strips into the video sequence editor for editing and then planned to output them into a movie file. When you downloaded the file, those film strips are targeted to render out when you hit the render button. Since those sequence file are not pack within the blend file ... you would get transparent frames.



Note what cegaton said below in the comment would also work.